To put a human face on our ancestors, scientists from the Senckenberg Research Institute used sophisticated methods to form 27 model heads based on tiny bone fragments, teeth and skulls collected from across the globe.
The heads are on display for the first time together at the Senckenberg Natural History Museum in Frankfurt, Germany.
This model is Sahelanthropus tchadensis, also nicknamed "Toumai," who lived 6.8 million years ago. Parts of its jaw bone and teeth were found nine years ago in the Djurab desert in Chad. It's one of the oldest hominid specimens ever found.

Washington State University; Sven Traenkner (

View Caption+#2: Australopithecus afarensis

With each new discovery, paleoanthropologists have to rewrite the origins of man's ancestors, adding on new branches and tracking when species split.
This model was fashioned from pieces of a skull and jaw found among the remains of 17 pre-humans (nine adults, three adolescents and five children) which were discovered in the Afar Region of Ethiopia in 1975.
The ape-man species, Australopithecus afarensis, is believed to have lived 3.2 million years ago. Several more bones from this species have been found in Ethiopia, including the famed "Lucy," a nearly complete A. afarensis skeleton found in Hadar.

Minnesota State University; Sven Traenkner (c

View Caption+#3: Australopithecus africanus

Meet "Mrs. Ples," the popular nickname for the most complete skull of an Australopithecus africanus, unearthed in Sterkfontein, South Africa in 1947.
It is believed she lived 2.5 million years ago (although the sex of the fossil is not entirely certain).
Crystals found on her skull suggest that she died after falling into a chalk pit, which was later filled with sediment.
A. africanus has long puzzled scientists because of its massive jaws and teeth, but they now believe the species' skull design was optimal for cracking nuts and seeds.

Proceedings of the National Academy of Sci

View Caption+#4: Paranthropus aethiopicus

The skull of this male adult was found on the western shore of Lake Turkana in Kenya in 1985. The shape of the mouth indicates that he had a strong bite and could chew plants.
He is believed to have lived in 2.5 million years ago and is classified as Paranthropus aethiopicus. Much is still unknown about this species because so few reamins of P. aethiopicus have been found.

Smithsonian Museum; Sven Traenkner (c), "Safa

View Caption+#5: Paranthropus boisei

Researchers shaped this skull of "Zinj," found in 1959. The adult male lived 1.8 million years ago in the Olduvai Gorge of Tanzania.
His scientific name is Paranthropus boisei, though he was originally called Zinjanthropus boisei -- hence the nickname.
First discovered by anthropologist Mary Leakey, the well-preserved cranium has a small brain cavity.
He would have eaten seeds, plants and roots which he probably dug with sticks or bones.

Sven Traenkner (c), "Safari zum Urmenschen" (

View Caption+#6: Homo rudolfensis

This model of a sub-human species -- Homo rudolfensis -- was made from bone fragments found in Koobi Fora, Kenya, in 1972.
The adult male is believed to have lived about 1.8 million years ago. He used stone tools and ate meat and plants.
H. Rudolfensis' distinctive features include a flatter, broader face and broader postcanine teeth, with more complex crowns and roots. He is also recognized as having a larger cranium than his contemporaries.

Minnesota State University; Sven Traenkner (c

View Caption+#7: Homo ergaster

The almost perfectly preserved skeleton of the "Turkana Boy" is one of the most spectacular discoveries in paleoanthropology. Judging from his anatomy, scientists believe this Homo ergaster was a tall youth about 13 to 15 years old.
According to research, the boy died beside a shallow river delta, where he was covered by alluvial sediments.
Comparing the shape of the skull and teeth, H. ergaster had a similiar head structure to the Asian Homo erectus.

Sven Traenkner (c), "Safari zum Urmenschen" (

View Caption+#8: Homo heidelbergensis

This adult male, Homo heidelbergensis, was discovered in in Sima de los Huesos, Spain in 1993. Judging by the skull and cranium, scientists believe he probably died from a massive infection that caused a facial deformation.
The model, shown here, does not include the deformity.
This species is believed to be an ancestor of Neanderthals, as seen in the shape of his face.
"Miquelon," the nickname of "Atapuerca 5", lived about 500,000 to 350,000 years ago and fossils of this species have been found in Italy, France and Greece.

Sven Traenkner (c), "Safari zum Urmenschen" (

View Caption+#9: Homo neanderthalensis

The "Old Man of La Chapelle" was recreated from the skull and jaw of a Homo neanderthalensis male found near La Chapelle-aux-Saints, in France in 1908. He lived 56,000 years ago.
His relatively old age, thought to be between 40 to 50 years old, indicates he was well looked after by a clan.
The old man's skeleton indicates he suffered from a number of afflictions, including arthritis, and had numerous broken bones.
Scientists at first did not realize the age and afflicted state of this specimen when he was first discovered. This led them to incorrectly theorize that male Neanderthals were hunched over when they walked.

Sven Traenkner (c), "Safari zum Urmenschen" (

View Caption+#10: Homo floresiensis

The skull and jaw of this female "hobbit" was found in Liang Bua, Flores, Indonesia, in 2003. She was about 1 meter tall (about 3'3") and lived about 18,000 years ago.
The discovery of her species, Homo floresiensis, brought into question the belief that Homo sapiens was the only form of mankind for the past 30,000 years.
Scientists are still debating whether Homo floresiensis was its own species, or merely a group of diseased modern humans. Evidence is mounting that these small beings were, in fact, a distinct human species.

Sven Traenkner (c), "Safari zum Urmenschen" (

View Caption+#11: Homo sapiens

Bones can only tell us so much. Experts often assume or make educated guesses to fill in the gaps in mankind's family tree, and to develop a sense what our ancestors may have looked like.
Judging from skull and mandible fragments found in a cave in Israel in 1969, this young female Homo sapien lived between 100,000 and 90,000 years ago. Her bones indicate she was about 20 years old. Her shattered skull was found among the remains of 20 others in a shallow grave.

Ancient stone artifacts recently excavated from Saudi Arabia possess similarities to items of about the same age in Africa -- a discovery that could provide clues to how humans dispersed out of Africa, researchers say.

Modern humans originated about 200,000 years ago in Africa. However, scientists have long debated when and how the modern human lineage spread out of Africa.

"Understanding how we originated and colonized the world remains one of the most fascinating and enduring questions, because it is our story as humans," said lead study author Eleanor Scerri, an archaeologist at the University of Bordeaux in France.

In addition, stone artifacts recently unearthed in the Arabian Desert date to at least 100,000 years ago. This could be evidence of an early modern-human exodus out of Africa, scientists say. However, it's possible that these artifacts weren't created by modern humans; a number of now-extinct human lineages existed outside Africa before or at the same time when modern humans migrated there. For instance, the Neanderthals, the closest known extinct relatives of modern humans, lived in both Europe and Asia around that time. [See Images of Our Closest Human Ancestor]

To help shed light on the role the Arabian Peninsula might have played in the history of modern humans, scientists compared stone artifacts recently excavated from three sites in the Jubbah lake basin in northern Saudi Arabia with items from northeast Africa excavated in the 1960s. Both sets of artifacts were 70,000 to 125,000 years old. Back then, the areas that are now the Arabian and Sahara deserts were far more hospitable places to live than they are now, which could have made it easier for modern humans and related lineages to migrate out of Africa.

"Far from being a desert, the Arabian Peninsula between 130,000 and 75,000 years ago was a patchwork of grasslands and savanna environments, featuring extensive river networks running through the interior," Scerri said.

The northeast African stone tools the researchers analyzed were similar to ones previously found near modern-human skeletons. The scientists found that stone artifacts at two of the three Arabian sites were "extremely similar" to the northeast African stone tools, Scerri told Live Science. At the very least, Scerri said, this finding suggests that there was some level of interaction between the groups in Africa and those in the Arabian Peninsula, and might hint that these Arabian tools were made by modern humans.

Surprisingly, Scerri said, tools from the third Arabian site the researchers analyzed were "completely different." "This shows that there was a number of different tool-making traditions in northern Arabia during this time, often in very close proximity to each other," she said.

One possible explanation for these differences is that the artifacts were made by different human lineages. Future research needs to uncover skeletal remains with ancient tools unearthed from the Arabian Peninsula to help solve this mystery, Scerri noted. Unless skeletal remains are found near such artifacts, it will remain uncertain whether modern humans or a different human lineage might have made them.

"It seems likely that there were multiple dispersals into the Arabian Peninsula from Africa, some possibly very early in the history of Homo sapiens," Scerri said. "It also seems likely that there may have been multiple dispersals into this region from other parts of Eurasia. These features are what make the Arabian Peninsula so interesting."

Ancient migrants out of Africa and from Eurasia might have encountered a number of different populations in the Arabian Peninsula, Scerri said. Some of these groups may have adapted to their environment more than others had, which raises the intriguing question: "Did the exchange of genes and knowledge between such groups contribute to our ultimate success as a species?" Scerri said.

The scientists detailed their findings online Aug. 8 in the Journal of Human Evolution.